The MAX 9 is getting its butt kicked by the Airbus A321neo or "new engine option." Even though the 737 MAX is the fastest-selling plane in Boeing history, only a small percentage of the 3,621 orders the company has taken have been for the MAX 9. In fact, with 1,384 orders, the A321neo is out-selling the MAX9 at a rate of five planes to one.via Business Insider